I found myself just a few weeks back standing in the middle of a main road fending off traffic while a mother duck crossed with her 13 babies lol
never mind I had to leave my baby in the pram on side of the road while I did this
I don't want to bring hopes down, but to be honest, in most sewers, the drop down is pretty high, they might've died on impact. If not, then the sewage water will have overcame them with toxins and poisons. Sorry if that sounds cruel, but that's reality. I mean, them surviving is also another possibility, but it doesn't look too good. I hope they did rescue them in time. Poor little duckies
I have some good news, I saw the program on Animal Planet!
The person who took the photos did call the fire-brigade and they did rescue all the little ducks. The mother duck stood there until each and every one of them were rescued and only after that did she turn around and walk away. She knew EXACTLY how many ducklings she had.